804 research outputs found

    Adsorption and catalytic activity of glucose oxidase accumulated on OTCE upon the application of external potential

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    This article describes the adsorption of glucose oxidase (GOx) onto optically transparent carbon electrodes (OTCE) under the effect of applied potential and the analysis of the enzymatic activity of the resulting GOx/OTCE substrates. In order to avoid electrochemical interferences with the enzyme redox center, control electrochemical experiments were performed using flavin adenine dinucleotide (FAD) and GOx/OTCE substrates. Then, the enzyme adsorption experiments were carried out as a function of the potential applied (ranged from the open circuit potential to +950. mV), the pH solution, the concentration of enzyme, and the ionic strength on the environment. The experimental results demonstrated that an increase in the adsorbed amount of GOx on the OTCE can be achieved when the potential was applied. Although the increase in the adsorbed amount was examined as a function of the potential, a maximum enzymatic activity was observed in the GOx/OTCE substrate achieved at +800. mV. These experiments suggest that although an increase in the amount of enzyme adsorbed can be obtained by the application of an external potential to the electrode, the magnitude of such potential can produce detrimental effects in the conformation of the adsorbed protein and should be carefully considered. As such, the article describes a simple and rational approach to increase the amount of enzyme adsorbed on a surface and can be applied to improve the sensitivity of a variety of biosensors.Fil: Benavidez, Tomás Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina. University of Texas; Estados UnidosFil: Torrente, Daniel. University of Texas; Estados UnidosFil: Marucho, Marcelo. University of Texas; Estados UnidosFil: Garcia, Carlos D.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina. University of Texas; Estados Unido

    Muon anomalous magnetic moment in supersymmetric scenarios with an intermediate scale and nonuniversality

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    We analyze the anomalous magnetic moment of the muon (a_{\mu}) in supersymmetric scenarios. First we concentrate on scenarios with universal soft terms. We find that a moderate increase of a_{\mu} can be obtained by lowering the unification scale M_{GUT} to intermediate values 10^{10-12} GeV. However, large values of \tan \beta are still favored. Then we study the case of non-universal soft terms. For the usual value M_{GUT}~10^{16} GeV, we obtain a_{\mu} in the favored experimental range even for moderate \tan \beta regions \tan\beta ~ 5$. Finally, we give an explicit example of these scenarios. In particular, we show that in a D-brane model, where the string scale is naturally of order 10^{10-12} GeV and the soft terms are non universal, a_{\mu} is enhanced with low \tan\beta.Comment: Final version to appear in Phys. Rev. D. Conventions clarified, results in the figures improve

    Obituary

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    Prison de-radicalization strategies, programs and risk assessment tools in Europe

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    open3noWith financial support from the Criminal Justice Programme of the European Union Call: JUST-AG-2016-03 Project Number: 763710 Project Acronym: PRP Duration (months): 24 Project Title: European Prison Observatory. Prison de-radicalization strategies, programmes and risk assessment tools in Europe. Coordinator: ANTIGONE ONLUS Alvise Sbraccia wrote the Part One of this Report; Daniela Ronco wrote Part Two, chapters 1, 2, 3, 4, 5, 6, 7, 8; Giovanni Torrente wrote Part Two, chapters 9-10. The conclusions have been written by all the authorsThis project’s goal is to assess strategies and programmes which prevent, deter and counter radicalization in prison and identify and analyse good practices regarding new or existing de-radicalization, disengagement and rehabilitation programmes and risk assessment tools. The analysis has been carried out having in mind the international and European standards for the the protection of detainees' rights. Research incorporates qualitative and quantitative data analysis on official government documents and interviews with stakeholders from prison administration and management, prison staff, Imams, chaplains and other religious representatives.openDaniela Ronco, Alvise Sbraccia, Giovanni TorrenteDaniela Ronco, Alvise Sbraccia, Giovanni Torrent

    Biphasic Epoxidation Reaction in the Absence of Surfactants - Integration of Reaction and Separation Steps in Microtubular Reactors

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    This paper presents a paradigm shift with respect to the current direction of biphasic reactions in surfactant-free emulsions. Herein, the contact area between both phases is simply sustained by the reactor design (i.e., diameter of the tubular reactor) compared to the current trend of using reversible/switchable emulsions where the addition of an external agent (e.g., bistable surfactant, magnetic particles, etc.) is required. In this way, temporally stable phase dispersions using microtubular reactors facilitate the integration of reaction and separation steps in biphasic systems without the need for energy-intensive downstream separation steps. In this study, we demonstrate this innovative tool in the epoxidation reaction of sunflower oil with hydrogen peroxide. Using a combination of mechanistic and kinetic studies, we demonstrate that the poor solubility of the catalytic species in the oil phase may be used advantageously, allowing ready recyclability of catalyst (and oxidant) in consecutive runs.The authors thank the UK Engineering and Physical Sciences Research Council for funding via the EPSRC Doctoral Training Centre in Sustainable Chemical Technologies, University of Bath (Grant No. EP/G03768X/1) and a L.T.-M.’s Fellowship award (Grant No. EP/L020432/2).This is the author accepted manuscript. The final version is available from the American Chemical Society via http://dx.doi.org/10.1021/acssuschemeng.6b0028

    Relic Neutralino Density in Scenarios with Intermediate Unification Scale

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    We analyse the relic neutralino density in supersymmetric models with an intermediate unification scale. In particular, we present concrete cosmological scenarios where the reheating temperature is as small as O\cal{O} 110001 - 1000 MeV). When this temperature is associated to the decay of moduli fields producing neutralinos, we show that the relic abundance increases considerably with respect to the standard thermal production. Thus the neutralino becomes a good dark matter candidate with 0.1\lsim \Omega h^2 \lsim 0.3, even for regions of the parameter space where large neutralino-nucleon cross sections, compatible with current dark matter experiments, are present. This is obtained for intermediate scales MI10111014M_I\sim 10^{11}-10^{14} GeV, and moduli masses mϕ1001000m_\phi\sim 100-1000 GeV. On the other hand, when the above temperature is associated to the decay of an inflaton field, the relic abundance is too small.Comment: Latex, 11 pages, 2 figure

    Cannibalization of previous Na-rich clinopyroxenes by ascending basic magmas of the Garrotxa Volcanic Field (NE Spain)

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    The Garrotxa Volcanic Field (GVF) is a Quaternary monogenetic volcanic field belonging to the NE Spain volcanic province, recording a Neogene alkaline intraplate magmatic activity consequence of the rift-type extensional tectonics that has affected the eastern margin of Iberia since late Oligocene

    Mantle source heterogeneity beneath the Garrotxa Volcanic Field (NE Spain)

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    The Neogene volcanism in NE Spain, which is related to the rift-type extensional tectonics affecting the eastern margin of Iberia since late Oligocene, is well represented in the basalts and basanites from the Garrotxa Volcanic Field (GVF)

    Effect of support of Co-Na-Mo catalysts on the direct conversion of CO<inf>2</inf> to hydrocarbons

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    This study of the effect of support of Co-Na-Mo based catalysts on the direct hydrogenation of CO2_2 into hydrocarbons (HC) provides guidelines for the design of catalysts for CO2_2 conversion. We demonstrate that the surface area of the support and the metal-support interaction have a key role determining the cobalt crystallite size and consequently the activity of the system. Cobalt particles with sizes <2 nm supported on MgO present low reverse water gas shift conversion with negligible Fischer-Tropsch activity. Increasing the cobalt particle size to ~15 nm supported on SiO2_2 and ZSM-5 supports not only substantially increases the CO2_2 conversion but it also provides high HC selectivities. Further increase of the cobalt particle size to 25–30 nm has a detrimental effect on the global CO2_2 conversion with HC:CO ratios below 1, however, lower methane selectivity and enhanced formation of unsaturated HC products are achieved. Additionally, the metal-support interaction potentially also has a strong effect on the growth chain probability of the formed hydrocarbons, increasing as the metal-support interaction increases. These evidences demonstrate that CO2_2 conversion and hydrocarbon distribution can be tuned towards desired products by controlled catalyst design.University of BathThis is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.jcou.2016.06.00
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